1. Field of the Invention
The present invention relates to an image generating apparatus, image generating program, image generating program recording medium and image generating method. Specifically, the present invention relates to an image generating apparatus that displays an image of a virtual three-dimensional space on a display screen.
2. Description of the Related Art
Conventionally, a video game apparatus is known, which displays a virtual three-dimensional space, a player character that moves in accordance with an operation input by a player and other objects in the three-dimensional space. Such video game apparatus places a virtual camera in the virtual three-dimensional space and generates an image of a range viewed with the virtual camera as a viewpoint. In this case, a cross point of a visual axis of the virtual camera with a predetermined angle and an object in the three-dimensional space is set as a point of gaze. The video camera moves to follow the player character with such point of gaze being set on the player character. Thus, a video game advances while always displaying the player character in the virtual three-dimensional space.
As game advances, the situation may occur sometimes in which an obstacle object such as a wall exists between the virtual camera and the player character along the visual axis and the player character exists near the wall and the like.
In this case, as shown in FIG. 1A, a virtual camera 62 is moved away from a wall 26 towards a player character 65. At the same time, the angle of a visual axis L of the virtual camera 62 is changed to vertical direction to set the point of gaze on the player character 65. Thus, as shown in FIG. 1A′, the player character 65 is displayed on a display screen 61 without being interrupted by the wall.
However, when the angle of the visual axis L of the virtual camera 62 is changed in the virtual direction from the normal angle, a visual field V of the virtual camera 62 is also changed in the vertical direction, and thereby an enemy character 67 is kept outside of the visual field V. As a result, as shown in FIG. 1A′, the enemy character 67 is not displayed on the display screen 61.
In view of the above, Japanese Unexamined Patent Publication No. 2004-3451572 describes using two virtual cameras, i.e., one virtual camera which is used in normal times and another virtual camera, and generating an image using the other virtual camera switched from the virtual camera used in the normal times so as to display the image that is not interrupted by obstacle objects.
However, an image processing procedure may become complicated because of generating images by switching the virtual camera to be used from one used in the normal times to another as described in the above-mentioned Japanese Unexamined Patent Publication.